The heart operates as a pump which causes blood to flow throughout the body. In various cases, patients suffer from blockages and/or pressure elevation and it is required to keep a passage open for blood flow. In other patients, an undesired flow path opens and it is required to close the flow path. In such patients, stents, valves or seals are implanted to achieve a required blood flow pattern.
An article titled “Creation with a stent of an unrestrictive lasting atrial communication”, by Marc Gewillig et al., Cardiol Young 2002; 12(4):404-7, the disclosure of which is incorporated herein by reference, describes use of a stent to create an unrestrictive and atrial communication. An article titled “Modified technique of stent fenestration of the atrial septum”, Stümper et al., 89 (10): 1227, Heart 2003, the disclosure of which is incorporated herein by reference, describes placing a stent across a fenestration and expanding the stent by a balloon.
Various closure devices are known in the art.
PCT publication WO 2005/027752, filed Sep. 13, 2004, the disclosure of which is incorporated herein by reference, describes a closure device formed of a pair of anchor members and a center flexible joint, which press on the septum and hold it closed.
US patent publication 2006/0122647 to Callaghan et al., published Jun. 8, 2006, describes an occlusion device formed of a polymer tube that includes distal and proximal ends for securing to opposite ends of the septum.
US patent publication 2007/0010852, to Blaeser et al., published Jan. 11, 2007, the disclosure of which is incorporated herein by reference, describes a device for sealing a patent foramen ovale (PFO) in the heart. The device includes a right atrial member including a plurality of arms and a cover attached to the arms, and a left atrial anchor including a plurality of arms.
There are also various valves known in the art.
PCT publication WO 2005/074367, published Aug. 18, 2005, the disclosure of which is incorporated herein by reference, describes a plurality of valves and methods of anchoring the valves in the heart. One anchoring method described is use of support arms opposite each other on both sides of a wall through which the valve passes.
US patent publication 2006/0167541 to Lattouf, published Jul. 27, 2006, disclosure of which is incorporated herein by reference, describes a valve formed of a tube with hooks on both ends for anchoring in the heart and a leaflet valve placed in the tube.
US patent publication 2004/0162514 to Alferness, the disclosure of which is incorporated herein by reference, describes a pop-off valve for placement in the heart between the left and right atriums. The valve includes spikes, referred to as anchor guides, which pierce a wall of the heart and thus keep the device in place. Such piercing is not always desirable as it may damage heart tissue.
US patent publication 2006/0116710 to Corcoran et al., the disclosure of which is incorporated herein by reference, describes an occlusion device having a relatively low profile against the occluded tissue.